Where the Vestries of any Parishes mentioned in either of the Schedules (A.) and (B.) to this Act now act jointly or in union, or exercise any Powers or Privileges jointly or in union, or elect Guardians, Directors, Trustees, or other Persons whomsoever whose Offices are not expressed to be determined by this Act for any joint Purposes, the Vestries of such Parishes elected under this Act may act jointly or in union, and shall have the like Powers and Privileges jointly or in union, and elect for such joint Purposes in like Manner and with the like Effect; and where in any of the said Parishes any Guardians, Directors, Trustees, or other Persons whosoever whose Offices are not expressed to be determined by this Act are now by Law elected out of the Vestry of any Such Parish, such Guardians, Directors, Trustees, or other Persons as aforesaid may be elected out of or from the Vestrymen and Persons who under this Act are eligible as Vestrymen for the same Parish; and the Office of no such Guardian, Director, Trustee, or other Person shall be determined by reason of his ceasing to be a Vestryman in consequence of the passing of this Act; but every such Guardian, Director, Trustee, or other Person shall continue in Office until such Time as he would otherwise have ceased to hold his Office.